Conventionally, error control techniques have been used to guarantee the transmission quality satisfying QoS (Quality of Service) or the like in communication systems in which packet transmission is performed. As this error control technique, Non-patent Documents 1 and 2 describe Hybrid-ARQ (HARQ) obtained by combining ARQ (Automatic Repeat reQuest) and error correcting coding such as turbo coding. HARQ is a technique in which a reception apparatus requests retransmission to a transmission apparatus when detecting an error in a received signal, and performs decoding processing on a combined signal of the repeatedly received signal and already received signal.
Particularly, as HARQ, Chase Combining (CC) and IR (Incremental Redundancy) are known well. For example, in HARQ using CC, when an error is detected in a received packet, retransmission of absolutely the same packet is requested. By combining these two packets, it is possible to increase the reception quality. Meanwhile, in HARQ using IR, since redundant bits are divided to retransmit sequentially bit by bit, as the number of retransmission times increases, the coding rate is decreased, and it is possible to strengthen the error correcting capability.    Non-patent Document 1: D. Chase, “Code combining—A maximum likelihood decoding approach for combing and arbitrary number of noisy packets,” IEEE Trans. Commun., vol. COM-33, pp. 385-393, May 1985.    Non-patent Document 2: Hagenauer, “Rate-compatible punctured convolutional codes (RCPC codes) and their application,” IEEE Trans. Commun., vol. 36, pp. 389-400, April 1988.